Owners manual states not to leave devices plugged in when not in use. It's only some Xmas lights, so I'm wondering what if any would keeping them plugged in be a problem. I'm not an electrician, but if there is no current at the socket when the truck's ignition is off, what would be the problem?
If I wanted to do the smoked/blackout style taillights thing, I would have my local window tint shop do it for only $60.00. He did the Ford front grill logo for $20.00.